Helicopter vibration control system and rotary force generator for canceling vibrations

ABSTRACT

Helicopter rotating hub mounted vibration control system for a rotary wing hub having periodic vibrations while rotating at an operational rotation frequency. The vibration control system includes a housing attachable to the rotary wing hub and rotating with the hub at the operational frequency. The housing is centered about the rotary wing hub axis of rotation and has an electronics housing cavity subsystem and an adjacent rotor housing cavity subsystem. The rotor housing cavity contains a first coaxial ring motor with a first rotor and imbalance mass and a second coaxial ring motor with a second rotor and imbalance mass. The electronics housing cavity contains an electronics control system which receives sensor outputs and electrically controls and drives the first motor and the second motor such that the first imbalance mass and the second imbalance mass are driven at a vibration canceling rotation frequency greater than the operational rotation frequency wherein the helicopter rotary wing hub periodic vibrations are reduced.

CROSS REFERENCE

This application is a Continuation of U.S. patent application Ser. No.11/215,388 filed on Aug. 30, 2005 now U.S. Pat. No. 7,448,854, whichclaims the benefit of U.S. Provisional Patent Application Ser. No.60/605,470 filed on Aug. 30, 2004, both of which the benefit of areclaimed and are incorporated by reference.

FIELD OF THE INVENTION

The invention relates to a method/system for controlling problematicrotary wing vibrations. More particularly the invention relates to amethod and system for controlling helicopter vehicle vibrations,particularly a method and system for canceling problematic rotatinghelicopter vibrations.

BACKGROUND OF THE INVENTION

Helicopter vibrations are particularly troublesome in that they cancause fatigue and wear on the equipment and occupants in the aircraft.In vehicles such as helicopters, vibrations are particularly problematicin that they can damage the actual structure and components that make upthe vehicle in addition to the contents of the vehicle.

There is a need for a system and method of accurately and economicallycanceling rotating vehicle vibrations. There is a need for a system andmethod of accurately controlling rotary wing vibrations in a weightefficient manner. There is a need for a method of controlling vibrationsin a helicopter hub so that the vibrations are efficiently minimized.There is a need for a robust system of controlling vibrations in ahelicopter so that the vibrations are efficiently minimized. There is aneed for a method/system for controlling problematic helicoptervibrations.

SUMMARY OF THE INVENTION

In an embodiment the invention includes a rotary wing aircrafthelicopter rotating hub mounted vibration control system for ahelicopter rotary wing hub having a periodic vibration while rotating ata helicopter operational rotation frequency. The helicopter rotating hubmounted vibration control system includes an annular ring rotary housingattachable to the helicopter rotary wing hub and rotating with thehelicopter rotary wing hub at the helicopter operational rotationfrequency. The annular ring housing is centered about the rotary winghub axis of rotation and has an electronics housing cavity subsystem andan adjacent coaxial rotor housing cavity subsystem. The rotor housingcavity subsystem contains a first coaxial frameless AC ring motor havinga first rotor with a first imbalance mass and a second coaxial framelessAC ring motor having a second rotor with a second imbalance mass. Theelectronics housing cavity subsystem contains an electronics controlsystem which receives sensor outputs and electrically controls anddrives the first coaxial frameless AC ring motor and the second coaxialframeless AC ring motor such that the first imbalance mass and thesecond imbalance mass are directly driven at a vibration cancelingrotation frequency greater than the helicopter operational rotationfrequency wherein the helicopter rotary wing hub periodic vibration isreduced.

In an embodiment the invention includes a rotary wing aircrafthelicopter rotating vibration control system for a helicopter rotarywing hub having a periodic vibration while rotating at a helicopteroperational rotation frequency about a rotary wing axis of rotation. Thehelicopter rotating vibration control system includes a rotary housingcentered about and encompassing the rotary wing axis of rotation withthe rotary housing rotating at the helicopter operational rotationfrequency. The rotating rotary housing contains a first coaxial ringmotor coaxially centered about the rotary wing axis of rotation. Thefirst coaxial ring motor has a first rotor with a first imbalance massconcentration. The rotating rotary housing contains a second coaxialring motor coaxially centered about the rotary wing axis of rotationwith the second coaxial ring motor having a second rotor with a secondimbalance mass concentration. The rotating rotary housing contains anelectronics control system which controls a speed and a phase of thefirst coaxial ring motor and the second coaxial ring motor such that thefirst imbalance mass concentration and the second imbalance massconcentration are directly driven at a whole number multiple vibrationcanceling rotation frequency greater than the helicopter operationalrotation frequency wherein the helicopter rotary wing hub periodicvibration is reduced.

In an embodiment the invention includes a method of controlling aperiodic vibration of a rotary wing aircraft helicopter with ahelicopter rotary wing hub, which rotates at an operational rotationfrequency. The method includes providing an annular ring housing havingan electronics housing cavity subsystem and an adjacent coaxial rotorhousing cavity subsystem. The rotor cavity subsystem contains a firstcoaxial ring motor coaxially centered about the rotary wing hub axis ofrotation. The first coaxial ring motor has a first rotor with a firstimbalance rotor eccentric mass concentration. The rotor cavity subsystemcontains a second coaxial ring motor having a second rotor with a secondimbalance rotor eccentric mass concentration, and a lubricant. Theelectronics housing cavity subsystem contains an electronics controlsystem which controls the speed and phase of the first coaxial ringmotor and the second coaxial ring motor. The method includes securingthe annular ring housing to the helicopter rotary wing hub with theannular ring housing rotating at the operational rotation frequency. Themethod includes directly electromagnetically driving the first rotor andthe second rotor at a whole number multiple vibration canceling rotationfrequency greater than the operational rotation frequency whilecontrolling the rotational phase position of the first imbalance rotoreccentric mass concentration and the second imbalance rotor eccentricmass concentration inorder to produce a rotating net force vector toinhibit and balances out the periodic vibration. The electronic controlsystem processes sensor inputs, determines the orientation and speed ofthe rotors, and calculates and modifies the speed and orientation of therotors inorder to cancel and balance out the unwanted vibrations.

In an embodiment the invention includes a method of making a helicopterrotating hub mounted vibration control system for a helicopter rotarywing hub having a periodic vibration while rotating at an operationalrotation frequency. The method includes providing a rotary housinghaving an electronics housing cavity and a rotor housing cavity. Theprovided rotor housing cavity preferably contains a first coaxialframeless ring driver motor having a first rotor with a first imbalancerotor eccentric mass concentration, a second coaxial frameless ringdriver motor having a second rotor with a second imbalance rotoreccentric mass concentration, with the rotor housing cavity including acircumferential surface. The provided electronics housing cavitypreferably contains an electronics control system which controls anddrives the speed and phase of the first coaxial frameless ring motor andthe second coaxial brushless frameless ring motor. The method preferablyincludes sealing a lubricant inside the rotor housing cavity, whereinthe lubricant collects along the circumferential surface when theannular ring housing rotates at the helicopter operational rotationfrequency.

In an embodiment the invention includes a vibration control balancersystem, which rotates about a center axis of rotation at an operationalrotation frequency. The rotating vibration balancer includes a firststator having a plurality of electromagnets with the electromagnetsperiodically spaced around the center axis of rotation, and a firstimbalance rotor having a mass concentration, the first imbalance rotorincluding magnets periodically spaced around the center axis of rotationwith the first imbalance rotor adjacent the first stator. The rotatingvibration balancer includes a second stator having a plurality ofelectromagnets periodically spaced around the center axis of rotation,and a second imbalance rotor having a having a mass concentration and aplurality of magnets periodically spaced around the center axis ofrotation, with the second imbalance rotor adjacent the second stator.The first stator electromagnets generate magnetic fields to move anddirectly drive the first imbalance rotor magnets and the first imbalancerotor eccentric mass concentration around the center axis of rotation ata vibration canceling rotation frequency greater than the operationalrotation frequency, and the second stator electromagnets directly driveand move the second imbalance rotor magnets and the second imbalancerotor eccentric mass concentration around the center axis of rotation atthe vibration canceling rotation frequency.

In an embodiment the invention includes a method of controlling aperiodic vibration of a helicopter with a helicopter rotary wing hub,which rotates about a center axis of rotation at an operational rotationfrequency. The method includes providing a first stator havingelectromagnets periodically spaced around the center axis of rotation,and providing a first imbalance rotor having an eccentric massconcentration and a plurality of magnets periodically spaced around thecenter axis of rotation. The method includes disposing and coupling thefirst imbalance rotor around the first stator such that the first statorelectromagnets directly drive the first imbalance rotor magnets and thefirst imbalance rotor eccentric mass concentration around the centeraxis of rotation. The method includes providing a second stator having aplurality of electromagnets periodically spaced around the center axisof rotation, and providing a second imbalance rotor having an eccentricmass concentration and a plurality of magnets periodically spaced aroundthe center axis of rotation. The method includes disposing and couplingthe second imbalance rotor around the second stator such that the secondstator electromagnets directly drive the second imbalance rotor magnetsand the second imbalance rotor eccentric mass concentration around thecenter axis of rotation. The method includes directly driving the firstrotor and the second rotor at a whole number multiple vibrationcanceling rotation frequency greater than the operational rotationfrequency while controlling the rotational position of the firstimbalance rotor eccentric mass concentration and the rotational positionof the second imbalance rotor eccentric mass concentration in order toproduce a rotating net force vector to inhibit the periodic vibration.

In an embodiment the invention includes a method of making a vibrationcontrol device, which rotates about a center axis of rotation at anoperational rotation frequency. The method includes providing a rotaryhousing. The method includes providing a first stator having a pluralityof electromagnets periodically spaced around the center axis ofrotation, and providing a first imbalance rotor having an eccentric massconcentration and a plurality of magnets periodically spaced around thecenter axis of rotation. The method includes coupling the firstimbalance rotor around first stator such that the first statorelectromagnets directly drive the first imbalance rotor magnets and thefirst imbalance rotor eccentric mass concentration around the centeraxis of rotation. The method includes providing a second stator having aplurality of electromagnets periodically spaced around the center axisof rotation and a second imbalance rotor having an eccentric massconcentration and a plurality of magnets periodically spaced around thecenter axis of rotation. The method includes coupling the secondimbalance rotor around the second stator such that the second statorelectromagnets directly drive the second imbalance rotor magnets and thesecond imbalance rotor eccentric mass concentration around the centeraxis of rotation. The method includes sealing the coupled firstimbalance rotor and the first stator and the coupled second imbalancerotor and the second stator in the rotary housing with a liquidlubricant.

In an embodiment the invention includes a rotary wing aircraft rotatingvibration control system for an aircraft rotary wing hub having aperiodic vibration while rotating at a rotary wing aircraft operationalrotation frequency about a rotary wing axis of rotation. The rotary wingaircraft rotating vibration control system includes a rotary housing,the housing centered about and encompassing the rotary wing axis ofrotation and rotating with the rotary wing hub at the operationalrotation frequency, the housing containing a first coaxial ring motorcoaxially centered about the rotary wing axis of rotation, the firstcoaxial ring motor having a first rotor with a first imbalance massconcentration, the housing containing a second coaxial ring motorcoaxially centered about the rotary wing axis of rotation, the secondcoaxial ring motor having a second rotor with a second imbalance massconcentration. The rotary wing aircraft rotating vibration controlsystem includes an electronics control system which controls a speed anda phase of the first coaxial ring motor and a speed and a phase of thesecond coaxial ring motor to drive the first imbalance massconcentration and the second imbalance mass concentration wherein therotary wing hub periodic vibration is reduced.In an embodiment the invention includes a method of controlling aperiodic vibration of an aircraft with a rotary hub which rotates at anoperational rotation frequency. The method includes providing an annularring housing having a coaxial rotor housing cavity subsystem, the rotorhousing cavity subsystem containing a first coaxial ring motor having afirst rotor with a first imbalance mass concentration, a second coaxialring motor having a second rotor with a second imbalance massconcentration, and a lubricant. The method includes securing the annularring housing to the rotary hub with the annular ring housing rotating atthe operational rotation frequency with the rotary hub. The methodincludes directly driving the rotation of the first rotor and the secondrotor by controlling the first coaxial ring motor and the second coaxialring motor to control the rotational position of the first imbalancemass concentration and the second imbalance mass concentration inorderto inhibit the periodic vibration.In an embodiment the invention includes a method of making a rotatinghub mounted vibration control system for a rotary wing hub having aperiodic vibration while rotating at an operational rotation frequency.The method includes providing a rotary housing having a rotor housingcavity, the rotor housing cavity containing a first coaxial ring motorhaving a first rotor with a first imbalance mass concentration, a secondcoaxial ring motor having a second rotor with a second imbalance massconcentration, the rotor housing cavity including a circumferentialsurface. The method includes providing an electronics control systemwhich controls a speed and a phase of the first coaxial ring motor and aspeed and a phase of the second coaxial ring motor. The method includesconnecting the electronics control system with the first coaxial ringmotor and the second coaxial ring motor. The method includes sealing alubricant inside the rotor housing cavity, wherein the lubricantcollects along the circumferential surface when the rotary housingrotates at the operational rotation frequency.In an embodiment the invention includes a rotating vibration controlsystem for a rotating machine having an operational rotation frequencywhich rotates about a center axis of rotation at the operationalrotation frequency, the rotating vibration control system comprised of arotating vibration control system rotary housing, the rotary housingcentered about and encompassing the center axis of rotation, the rotaryhousing rotating about the center axis at the operational rotationfrequency. The rotary housing includes a first stator having a pluralityof electromagnets, the electromagnets periodically spaced around thecenter axis of rotation, a first imbalance rotor having a massconcentration, the first imbalance rotor including a plurality ofmagnets periodically spaced around the center axis of rotation, thefirst imbalance rotor adjacent the first stator, a second stator havinga plurality of electromagnets, the electromagnets periodically spacedaround the center axis of rotation, a second imbalance rotor having amass concentration, the second imbalance rotor including a plurality ofmagnets periodically spaced around the center axis of rotation, thesecond imbalance rotor adjacent the second stator, wherein the firststator electromagnets directly drive the first imbalance rotor magnetsand the first imbalance rotor mass concentration around the center axisof rotation at a first imbalance rotor controlled speed and phase, andthe second stator electromagnets directly drive the second imbalancerotor magnets and the second imbalance rotor mass concentration aroundthe center axis of rotation at a second imbalance rotor controlled speedand phase. The rotating vibration control system includes an electronicscontrol system which controls a speed and a phase of the first rotor andthe second rotor.In an embodiment the invention includes a method of controlling aperiodic vibration of an aircraft with a rotary wing hub which rotatesabout a rotary wing hub center axis of rotation at an operationalrotation frequency. The method includes providing a first stator havinga plurality of electromagnets, the electromagnets periodically spacedaround the rotary wing hub center axis of rotation. The method includesproviding a first imbalance rotor, the first imbalance rotor having aneccentric mass concentration, the first imbalance rotor including aplurality of magnets periodically spaced around the rotary wing hubcenter axis of rotation. The method includes disposing and coupling thefirst imbalance rotor around the first stator such that the first statorelectromagnets directly drive the first imbalance rotor magnets and thefirst imbalance rotor eccentric mass concentration around the rotarywing hub center axis of rotation. The method includes providing a secondstator having a plurality of electromagnets, the electromagnetsperiodically spaced around the rotary wing hub center axis of rotation.The method includes providing a second imbalance rotor, the secondimbalance rotor having an eccentric mass concentration, the secondimbalance rotor including a plurality of magnets periodically spacedaround the rotary wing hub center axis of rotation. The method includesdisposing and coupling the second imbalance rotor around the secondstator such that the second stator electromagnets directly drive thesecond imbalance rotor magnets and the second imbalance rotor eccentricmass concentration around the rotary wing hub center axis of rotation.The method includes directly driving the first rotor at a first rotorcontrolling rotation frequency greater than the operational rotationfrequency around the rotary wing hub center axis of rotation anddirectly driving the second rotor at a second rotor controlling rotationfrequency greater than the operational rotation frequency around therotary wing hub center axis of rotation while controlling a rotationalposition of the first imbalance rotor eccentric mass concentrationaround the rotary wing hub center axis of rotation and a rotationalposition of the second imbalance rotor eccentric mass concentrationaround the rotary wing hub center axis of rotation inorder to inhibitthe periodic vibration.In an embodiment the invention includes a rotating vibration controlsystem which rotates about a center axis of rotation at an operationalrotation frequency, the rotating vibration control system for balancingout a periodic vibration force. The rotating vibration control systemincludes a first motor having a plurality of electromagnets, theelectromagnets periodically spaced around the center axis of rotation.The rotating vibration control system includes a first imbalance rotorhaving a mass concentration, the first imbalance rotor including aplurality of magnets periodically spaced around the center axis ofrotation, the first imbalance rotor and the first motor centered aboutthe axis of rotation, the first imbalance rotor driven by the firstmotor around the center axis of rotation at a vibration controllingrotation frequency greater than the operational rotation frequency. Therotating vibration control system includes a second imbalance rotor, thesecond imbalance rotor having a mass concentration, the second imbalancerotor centered about the axis of rotation wherein the second imbalancerotor mass concentration is movable relative to the first imbalancerotor mass concentration inorder to produce a rotating balancing netforce to cancel out the periodic vibration force.In an embodiment the invention includes a method of making a rotatingvibration control device which rotates about a center axis of rotationat an operational rotation frequency. The method includes providing arotary housing. The method includes providing a first stator having aplurality of electromagnets, the electromagnets periodically spacedaround the center axis of rotation. The method includes providing afirst imbalance rotor, the first imbalance rotor having an eccentricmass concentration, the first imbalance rotor including a plurality ofmagnets periodically spaced around the center axis of rotation. Themethod includes coupling the first imbalance rotor around first statorsuch that the first stator electromagnets directly drive the firstimbalance rotor magnets and the first imbalance rotor eccentric massconcentration around the center axis of rotation. The method includesproviding a second stator having a plurality of electromagnets, theelectromagnets periodically spaced around the center axis of rotation.The method includes providing a second imbalance rotor, the secondimbalance rotor having an eccentric mass concentration, the secondimbalance rotor including a plurality of magnets periodically spacedaround the center axis of rotation. The method includes coupling thesecond imbalance rotor around the second stator such that the secondstator electromagnets directly drive the second imbalance rotor magnetsand the second imbalance rotor eccentric mass concentration around thecenter axis of rotation. The method includes sealing the coupled firstimbalance rotor and the first stator and the coupled second imbalancerotor and the second stator in the housing.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary of the invention, andare intended to provide an overview or framework for understanding thenature and character of the invention as it is claimed. The accompanyingdrawings are included to provide a further understanding of theinvention, and are incorporated in and constitute a part of thisspecification. The drawings illustrate various embodiments of theinvention and together with the description serve to explain theprincipals and operation of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A-B show methods/systems for controlling helicopter vibrations.

FIG. 2A-B show helicopter rotating hub mounted vibration controlsystems.

FIG. 3A-D show helicopter rotating hub mounted vibration controlsystems.

FIG. 4A-F show methods/systems for controlling helicopter vibrations.

FIG. 5 shows helicopter rotating hub mounted vibration controlmethods/systems.

FIG. 6 shows a helicopter rotating hub mounted vibration controlsystems.

FIG. 7 shows a method/system for controlling helicopter vibrations.

FIG. 8A-E show helicopter rotating hub mounted vibration controlmethods/systems.

FIG. 9A-H show helicopter rotating hub mounted vibration controlmethods/systems.

FIG. 10A-C show helicopter rotating hub mounted vibration controlmethods/systems.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Additional features and advantages of the invention will be set forth inthe detailed description which follows, and in part will be readilyapparent to those skilled in the art from that description or recognizedby practicing the invention as described herein, including the detaileddescription which follows, the claims, as well as the appended drawings.

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings.

In an embodiment the invention includes a rotary wing aircrafthelicopter rotating hub mounted vibration balancing control system. Thehelicopter rotating hub mounted vibration control system includes anannular ring rotary housing for attachment with the helicopter with thehousing rotating at the helicopter operational rotation frequency. Theannular ring rotary housing is centered about the rotary wing hub axisof rotation. The housing preferably includes an electronics housingcavity and a rotor housing cavity. The rotor housing cavity contains afirst coaxial frameless AC ring motor having a first rotor with a firstimbalance rotor eccentric mass concentration and a second coaxialframeless AC ring motor having a second rotor with a second imbalancerotor eccentric mass concentration. The electronics housing cavitycontains a electronics control system which controls the position andmotion of the first coaxial frameless AC ring motor and the secondcoaxial frameless AC ring motor such that the first imbalance rotoreccentric mass concentration and the second imbalance rotor eccentricmass concentration are directly driven at a vibration canceling rotationfrequency greater than the helicopter operational rotation frequencywherein the helicopter rotary wing hub periodic vibration is reduced.Preferably the annular ring rotary housing is centered about the rotarywing hub axis of rotation, with both the electronics housing cavity andthe rotor housing cavity subsystems encompassing the helicopter rotarywing hub axis of rotation. Preferably the annular ring rotary housing,preferably with both the electronics housing cavity and the rotorhousing cavity subsystems, encompasses the helicopter rotor shaft.

FIG. 1 shows a rotary wing aircraft helicopter rotating hub mountedvibration control system 20 for a helicopter rotary wing hub 22 having aperiodic vibration 24 while rotating at a helicopter operationalrotation frequency 26. As shown in FIG. 2 helicopter rotating hubmounted vibration control system 20 includes an annular ring rotaryhousing 30. The annular ring rotary housing 30 is attached to thehelicopter rotary wing hub 22 and rotates with the helicopter rotarywing hub 22 and rotor shaft 29 at the helicopter operational rotationfrequency 26. The annular ring housing has an electronics housing cavitysubsystem 32 and a rotor housing cavity subsystem 34. Preferably thehousing 30 is centered about the rotary wing hub axis of rotation 28with both the electronics housing cavity subsystem and the rotor housingcavity subsystem encompassing the helicopter rotary wing hub axis ofrotation 28. The rotor housing cavity subsystem 34 contains a firstcoaxial brushless frameless AC ring motor 36 coaxially centered aboutthe rotary wing hub axis of rotation 28 and having a first imbalancerotor 38 with a first imbalance rotor eccentric mass concentration 40.The rotor housing cavity subsystem 34 contains a second coaxialframeless AC ring motor 42 coaxially centered about the rotary wing hubaxis of rotation 28 having a second rotor 44 with a second imbalancerotor eccentric mass concentration 46. Such as shown in FIG. 3,preferably the rotor housing cavity subsystem 34 contains a lubricant48, preferably a liquid fluid lubricant. The electronics housing cavitysubsystem 32 contains a electronics control system 50 which measures theperiodic vibration 24 and controls the speed, relative phase andabsolute phase of the first coaxial brushless frameless AC ring motor 36and the second coaxial brushless frameless AC ring motor 42 such thatthe first imbalance rotor and eccentric mass concentration 40 and thesecond imbalance rotor and eccentric mass concentration 46 are directlydriven at a whole number multiple vibration canceling rotation frequency52 greater than the helicopter operational rotation frequency 26 whereinthe helicopter rotary wing hub periodic vibration 24 is reduced. In apreferred embodiment the housing 30 is spinning at 1 per rev with thehelicopter rotary wing hub 22 and the imbalance rotor eccentric massconcentrations 40 and 46 spinning at N per rev, with the motors 36, 42directly driving the imbalance rotors 38 and 44 at (N−1) per revrelative to the housing 30 and in the same rotation direction as thehousing. This preferred embodiment N=4 is particularly applicable tofour bladed helicopters. As shown in FIG. 4, the first motor 36 producesa first rotating force 54 {F₁=mr w₁ ², where mr is the first rotorimbalance and w₁ is the first rotor spinning speed} and the second motor42 produces a second rotating force 56 which combine to produce arotating net force vector 58 to cancel the periodic vibration force 24.In preferred embodiments the rotor housing cavity subsystem 34 iscomprised of a first rotor upper cavity 60 and a second rotor lowercavity 62, with the upper and lower rotor cavity 60 and 62 separated sothat particle contaminates and spall debris from one rotor does notcontaminate other rotor, preferably with the upper and lower liquidlubricated cavities 60 and 62 liquidly isolated from each other.Preferably the first coaxial frameless AC ring motor first rotor 38 hasa lubricated bearing 64 for supporting the first rotor relative to thehousing 30, the first rotor bearing 64 lubricated by a liquid lubricant48, and the second coaxial frameless AC ring motor second rotor 44 has alubricated bearing 66 for supporting the second rotor relative to thehousing 30, with the second rotor bearing 66 lubricated by a lubricant48. Preferably the bearings 64 and 66 are thin section bearings with thethickness, height, width of the bearing (h) much less than the radius ofbearing r, h<<r. The first coaxial brushless frameless AC ring motorfirst rotor 38 has at least one target 68 and the second coaxialframeless AC ring motor second rotor 44 has at least one target 68, andthe rotor cavity subsystem contains at least one target sensing readhead 70 per rotor that senses the rotor targets 68, with the sensortargets and read heads providing for sensing the rotational position andmovement of the rotors 38 and 44, preferably with each rotor having aplurality of targets, preferably a plurality of multi-pole magnetictargets. Preferably the targets 68 and the sensor read heads 70 arelubricant resistant and tolerate and operate in the liquid lubricantenvironment of the rotor housing cavity subsystem 34. In embodiments thesensor read heads 70 are chosen from the sensor group consisting ofvariable reluctance sensors, resolvers, encoders, and magnetic sensorsthat sense the separate target magnets 68 of the rotors and tolerate thebearing lubricant environment inside the rotor housing cavity subsystem34, and have sensing operation that is lubricant resistant to the liquidoil splashing environment. In a preferred embodiment the sensor readheads 70 are Hall effect magnetic sensors for sensing rotor targetmagnets, with the Hall effect sensor positioned proximate the rotor andadapted to generate an output signal from the passing of the magnet withthe Hall effect sensor output received by the electronic control system.The target sensing read heads 70 transmit and communicate with theelectronics control system so the electronics control system tracks andhas information on the angular position of the rotors 38 and 44,particularly the orientation rotors and the rotational angular positionof the imbalance rotor eccentric mass concentrations 40 and 46. Therotational positions sensed by the target sensing read heads 70 is usedto drive the rotors with the motors and as feedback for the motor'samplifiers, and also is used to position the imbalance concentrations 40and 46 relative to the problematic rotor vibration as sensed by theaccelerometers of the electronics control system. The sensed rotorposition is fed back to the motor amplifiers inorder to commutate themotor and to control further driving of the rotor. Preferably at leasttwo vibration sensor accelerometers 72 are utilized by the electronicscontrol system to sense the vibration 24, and most preferably fourorthogonally positioned vibration sensor accelerometers 72 are spacedaround the axis of rotation 28 and sense the problematic periodicvibration 24, preferably with the vibration sensor accelerometersproviding for an X and Y coordinate system description of the sensedvibration 24 (ACCEL X, ACCEL Y). Preferably the electronics controlsystem receives input from the helicopter regarding the operation of thehelicopter, preferably including a helicopter tachometer input with asignal synchronized with the rotation speed helicopter operationalrotation frequency 26 of the helicopter rotary wing hub 22, and providesthe electronics control system with the speed of rotor blades and areference point for the phase of the helicopter rotary wing hub 22, suchas a three phase 400 Hz AC signal into a Tach Conditioning Circuit. Theelectronics control system drives the imbalance rotors 38 and 44 at theN per rev vibration canceling rotation frequency 52, and positions therotors eccentric masses 40 and 46 at relative rotational phases so thevibration 24 sensed by the accelerometers 72 is minimal, with rotorsphase and speed controlled to produce the net sum vibration cancelingforce 58 to counteract the problem vibration 24, preferably using agradient decent algorithm method. Preferably the electronics controlsystem accelerometers 72 sense the problem vibration 24, and theimbalance rotors 38 and 44 rotational phase positions are controlledwith each rotor producing a rotating force vector which add up to thenet disturbance force vector 58 with a direction and magnitude thatcounteract the problem vibration 24 and minimizes the vibration sensedby the accelerometers 72. The electronic control system processorreceives sensor outputs to determine the orientation and angularpositions of the rotors relative to the problematic vibrations andcalculates and modifies the movement of the rotors with generatedmagnetic fields inorder to change the amount of vibration sensed by theaccelerometers. Preferably the rotor housing cavity 34 includes acircumferential surface 74 that constrains the liquid lubricant 48 whilethe housing 30 is rotating at the helicopter operational rotationfrequency 26. With the rotation of the vibration control system housing30 the liquid lubricant collects against the wall surface 74. Preferablythe imbalance rotors include at least one lubricant mover 76 thatdisturbs the lubricant 48 collecting at the wall surface 74 inorder tocirculate the lubricant for the bearings 64 and 66. The lubricant mover76 may include the bearing and rotor members moving through thelubricant such that the liquid lubricant is moved and preferablycirculated through and around the bearings 64 and 66. Preferably thelubricant movers 76 radially extend out from the imbalance rotors 38 and44 rotors towards the circumferential surface 74 and with the lubricantmovers 76 moving and disturbing the constrained liquid lubricant 48. Asshown in FIG. 6-7, in an embodiment the lubricant movers 76 are radiallyextending scoops that scoop and direct the liquid lubricant towards thebearing. Preferably the lubricant movers 76 direct the lubricant 48inward towards axis of rotation 28, with the lubricant circulating andmoving through the bearings 64 and 66. Preferably the first rotorlubricated bearing 64 includes an outer race 78 secured to the housing30 proximate the rotor housing cavity circumferential surface 74 and aninner race 80 secured to the first rotor 38, with the ball bearingmoving rolling members 82 allowing the imbalance rotor 38 with innerrace 80 to spin faster than housing 30 with outer race 78. Preferablythe second rotor lubricated bearing 66 includes an outer race 78 securedto the housing 30 proximate the rotor housing cavity circumferentialsurface 74 and an inner race 80 secured to the second imbalance rotor44, with the ball bearing moving rolling members 82 allowing the secondimbalance rotor 44 with inner race 80 to spin faster than housing 30with outer race 78. Preferably the bearing moving rolling members 82 arelubricated in the liquid lubricant 48 constrained againstcircumferential surface 74, most preferably bathed and submersed in thelubricant. In an embodiment the first and second rotor cavities aresubstantially completely filled with the liquid lubricant 48. In apreferred embodiment the first and second rotor cavities are partiallyfilled with liquid lubricant 48, preferably such that when housing 30rotates at helicopter operational rotation frequency 26 the lubricatedbearings are lubricated by the liquid lubricant 48 but the rotors arenot submerged in the liquid, preferably with the rotors rotating througha non-liquid gas. Preferably the liquid lubricant 48 is sealed insidethe rotor housing cavity 34. In a preferred embodiment the electronicshousing cavity subsystem 32 is fluidly isolated from rotor cavitysubsystem 34, with the lubricant only in rotor cavities 60 and 62.

Preferably the helicopter rotating vibration electronics control systemopposingly orients the first imbalance mass concentration and the secondimbalance mass concentration at a transitioning rotation speed 53 lessthan the whole number multiple vibration canceling rotation frequency.As shown in FIG. 4C-D, preferably the invention includes opposinglyorienting the first imbalance mass concentration 40 and the secondimbalance mass concentration 46 at a transitioning rotation speed 53less than the whole number multiple vibration canceling rotationfrequency 52, preferably when the transitioning rotation speed is astartup speed less than the whole number multiple vibration cancelingrotation frequency with the system starting from a shutdown stop andspinning up towards the whole number multiple vibration cancelingrotation frequency or when the transitioning rotation speed is ashutting down speed less that the whole number multiple vibrationcanceling rotation frequency with the system shutting and slowing downfrom the full speed whole number multiple vibration canceling rotationfrequency down to shutdown stop. Preferably the first imbalance rotoreccentric mass concentration and the second imbalance rotor eccentricmass concentration are oriented opposed such that the vectors 56 and 54are opposed and cancel each other out while the transitioning rotationspeed is no more than ninety percent of the whole number multiplevibration canceling rotation frequency, preferably when thetransitioning rotation speed is no more than eighty percent of the wholenumber multiple vibration canceling rotation frequency, to provide asoft start and stop for the system. When a failure occurs with therotation of one of the imbalance rotors, such that a soft stop of thesystem is not achievable, the still operating nonfailed imbalance rotoris positioned and driven to oppose the disturbance force vector 24, withthe failed rotor slowing down to a stop, preferably byelectromagnetically braking the rotation of the failed rotor. As shownin FIG. 4E-F, in the event of a motor failure, the functioning motor isdriven and commanded to the angle of the resultant correction forcevector 58 just prior to the motor failure, with the still functioningmotor responding by positioning its imbalance rotor eccentric massconcentration to oppose the disturbance force vector 24, preferably withthe failed motor's imbalance rotor eccentric mass concentration motionbraked to a rest state. Just prior to failure both imbalance rotoreccentric mass concentrations are angularly positioned in order tocreate a resultant force vector 58 of magnitude and phase (desired phasephi) such that the disturbance force vector 24 is cancelled, uponfailure the still functioning motor drives its imbalance rotor eccentricmass concentration to the desired phase phi. Preferably the helicopterrotating vibration electronics control system includes anelectromagnetic braking circuit for electromagnetically braking arotation of the rotors. Preferably the invention includeselectromagnetically braking a rotation of the first imbalance rotor orthe second imbalance rotor, preferably when the operation of the motorof the imbalance rotor has failed. As shown in FIG. 9G-H,electromagnetic braking circuits 105 preferably complete the electriccircuits of electromagnet windings 104 and 106 to electromagneticallybrake the spinning imbalance rotor of the failed motor. Preferably thefailed rotor/motor is electromagnetically braked by the electromagneticbraking circuit 105 shorting the electromagnet windings 104 and 106, soinduced currents produced in the shorted electromagnet windings act toresist permanent magnets 94 moving around the axis of rotation 28. Theshorting of the electromagnet windings 104 and 106 completes theelectromagnetic braking circuit such that the rotation of the failedimbalance rotor is stopped. Preferably electromagnetically braking thefailed rotor by shorting the electromagnet windings 104 and 106,includes utilizing a switch, relay, solid state switch, or FET (FieldEffect Transistor), that is preferably open when powered, such that theshorting of the windings with electromagnetic braking circuits 105 iscontrolled and utilized only for a motor failure.

In an embodiment the invention includes a rotary wing aircrafthelicopter rotating vibration control system 20 for a helicopter rotarywing hub 22 having a periodic vibration 24 while rotating at ahelicopter operational rotation frequency 26 about a rotary wing axis ofrotation 28. The helicopter rotating vibration control system 20includes a rotary housing 30 centered about and encompassing the rotarywing axis of rotation 28 with the rotary housing 30 rotating at thehelicopter operational rotation frequency 26. The rotating rotaryhousing 30 contains a first coaxial ring motor 36 coaxially centeredabout the rotary wing axis of rotation 28. The first coaxial ring motor36 has a first imbalance rotor 38 with a first imbalance rotor eccentricmass concentration 40. The rotating rotary housing 30 contains a secondcoaxial ring motor 42 coaxially centered about the rotary wing axis ofrotation 28 with the second coaxial ring motor having a second imbalancerotor 44 with a second imbalance rotor eccentric mass concentration 46.The rotating rotary housing 30 contains an electronics control system 50which controls a speed and a phase of the first coaxial ring motor 36and the second coaxial ring motor 42 such that the first imbalance rotoreccentric mass concentration and the second imbalance rotor eccentricmass concentration are directly driven at a whole number multiplevibration canceling rotation frequency 52 greater than the helicopteroperational rotation frequency 26 wherein the helicopter rotary wing hubperiodic vibration 24 is reduced and minimized. Preferably the rotatingrotary housing 30 is comprised of an annular ring shape centered aboutand encompassing the rotary wing axis of rotation 28. Preferably therotating rotary housing 30 encompasses the rotor shaft 29, andpreferably is attached to and rotates with the helicopter rotary winghub 22 at the helicopter operational rotation frequency. Preferably therotary housing 30 has an electronics housing cavity subsystem 32 and anadjacent coaxial rotor housing cavity subsystem 34, preferably theannular ring rotary housing 30 centered about the rotary wing hub axisof rotation 28, with both cavity subsystems encompassing and centeredabout helicopter rotary wing hub axis of rotation 28. Preferably thefirst and second coaxial ring motors 36 and 42 are brushless ringmotors, and most preferably frameless AC ring motors. Preferably theelectronics control system 50 measures the periodic vibration 24,preferably with accelerometers 72, with the electronics control systemcontrolling the speed, relative phase, and absolute phase of theimbalance rotors eccentric mass concentrations to minimize the measuredvibration with the rotors gearlessly directly electromagnetically drivenat a vibration canceling rotation frequency greater than the helicopteroperational rotation frequency. In a preferred embodiment the housing 30is spinning at 1 per rev (the operational rotation frequency) and theimbalance rotor eccentric mass concentrations 40 and 46 are spinning at4 per rev, which is 3 per rev relative to housing 30 which is rotatingat 1 per rev. The first motor 36 produces a first rotating force 54, thesecond motor 42 produces a second rotating force 56, which combine toproduce a rotating net force vector 58 to cancel the periodic vibrationforce 24. Preferably the rotary housing 30 confines a fluid liquidlubricant 48. In a preferred embodiment the rotary housing 30 iscomprised of a first rotor upper cavity 60 and a second rotor lowercavity 62. Preferably the upper and lower rotor housing cavities areseparated so that particle contaminates and spall debris from oneimbalance rotor does not contaminate the other imbalance rotor,preferably with upper and lower liquid lubricated cavities liquidlyisolated from each other. Preferably the imbalance rotors 38 and 44 havelubricated bearings 64 and 66 for supporting the rotors relative to thehousing 30 and providing for the imbalance rotors to spin at a fasterrotational speed than the housing 30, preferably with the bearingslubricated by liquid lubricant 48. Preferably the bearings are thinsection bearings having bearing dimensions considerably less than theradius of the bearing (h<<r; h=thickness, height, width of bearing muchless than radius of bearing). Preferably the housing 30 includes acircumferential wall surface 74 that constrains the lubricant 48 whilethe housing is rotating at the helicopter operational rotationfrequency. Preferably the first rotor lubricated bearing 64 includes anouter race 78 secured to the housing 30 proximate the rotor housingcavity circumferential surface 74 and an inner race 80 secured to thefirst rotor 38, with the ball bearing moving rolling members 82 allowingthe imbalance rotor 38 with inner race 80 to spin faster than housing 30with outer race 78. Preferably the second rotor lubricated bearing 66includes an outer race 78 secured to the housing 30 proximate the rotorhousing cavity circumferential surface 74 and an inner race 80 securedto the second imbalance rotor 44, with the ball bearing moving rollingmembers 82 allowing the second imbalance rotor 44 with inner race 80 tospin faster than housing 30 with outer race 78. Preferably the bearingmoving rolling members 82 are lubricated in the liquid lubricant 48constrained against circumferential surface 74, most preferably bathedand submersed in the lubricant. In an embodiment the first and secondrotor cavities are substantially completely filled with the liquidlubricant 48. In a preferred embodiment the first and second rotorcavities are partially filled with liquid lubricant 48, preferably suchthat when housing 30 rotates at helicopter operational rotationfrequency 26 the lubricated bearings are lubricated by the liquidlubricant 48 but the rotors are not submerged in the liquid thusminimizing steady-state torque requirements that would arise fromviscous drag torque imposed by the liquid lubricant, preferably with therotors rotating through a non-liquid gas. Preferably the liquidlubricant 48 is sealed inside the rotor housing cavity 34. Preferablythe vibration control system housing contains a health monitoring sensor84 for monitoring a change in an operational characteristic of thevibration control system, preferably with the health monitoring sensorand health monitoring system incorporated into the electronics controlsystem. The health monitoring system with sensors 84 measure operationalperformance characteristics of the vibration control system 20, mostpreferably operational performance characteristics of the first andsecond rotors 38 and 44 and their rotation. Preferably the sensors 84monitor the health of the rotor bearings 64 and 66. In an embodiment thesensors 84 are temperature sensors that monitor the temperature of thebearings for a change in bearing operation temperature that signals abearing heat up and degradation in the operation of the bearing that mayresult from the onset of spalling. Preferably the health monitoringsystem with sensors 84 includes at least two temperature sensors, suchas thermocouples, preferably with at least one adjacent the bearing tomonitor the bearing temperature. Preferably the health monitoring systemutilizes a reference temperature to determine when the bearingtemperature is rising above the ambient temperature of the vibrationcontrol system 20. The health monitoring system sensors 84 monitor thebearing temperature differences to determine if a bearing is heating uptoo much in its operation, and when the measured temperature differenceexceeds a measured operational performance characteristic limitation,the vibration control system preferably through the electronics controlsystem provides for a correction change in the vibration control system,such as communicating and warning the helicopter user and maintainersthat bearing maintenance and/or replacement should be performed so thatthe bearing operation is corrected prior to failure of the bearing andfailure of the rotation of the rotor. The health monitoring systemsensors 84 catches the operation problem at the performance degradationstage, and provides a warning notification to the helicopter operator ormaintenance crew, to warn about replacement prior to bearing operationfailure. The health monitoring system is preferably linked with thehelicopter avionics system, with a warning maintenance signaltransmitted to the avionics system and operator. In an embodiment thehealth monitoring system sensors 84 monitors trends, with the systemstoring the sensor data and prior to failure of vibration control systemoperation identifying an approaching failure. In an embodiment thehealth monitoring system sensors 84 are accelerometers and monitorvibration signal levels at ball pass frequency bands to pickup on adeteriorating bearing race. Health monitoring system sensors 84 may bethe accelerometers 72, or preferably separate accelerometer sensors 84that monitor the ball pass frequency from each time the ball rolls overa bearing race problem spot and makes a vibration. Additionally inembodiments the health monitoring system senses, monitors, and warnsabout the vibration control system operation including the motor's 36and 42 currents, torques, and temperature. Preferably health monitoringsystem sensors 84 input data into a health monitoring system algorithm,with the algorithm outputting a notification to effect achange/correction to the vibration control system 20 such as service orreplacement. In an embodiment the output of the health monitoring systemalgorithm is a log of collected sensor data that is downloaded andanalyzed for performance and operation issues.

In an embodiment the invention includes a method of controlling aperiodic vibration 24 of a rotary wing aircraft helicopter with ahelicopter rotary wing hub 22, which rotates at an operational rotationfrequency 26. The method includes providing an annular ring rotaryhousing 30 having an electronics housing cavity subsystem 32 and anadjacent coaxial rotor housing cavity subsystem 34. The rotor cavitysubsystem 34 contains a first coaxial ring motor 36 coaxially centeredabout the rotary wing hub axis of rotation 28. The first coaxial ringmotor has a first imbalance rotor 38 with a first imbalance rotoreccentric mass concentration 40. The rotor cavity subsystem 34 containsa second coaxial ring motor 42 having a second imbalance rotor 44 with asecond imbalance rotor eccentric mass concentration 46, and a lubricant48. The electronics housing cavity subsystem 32 contains an electronicscontrol system 50 which controls the speed and phase of the firstcoaxial ring motor 36 and the second coaxial ring motor 42. The methodincludes securing the annular ring rotary housing 30 to the helicopterrotary wing hub 22 with the annular ring rotary housing rotating at theoperational rotation frequency 26. The method includes directly drivingthe first imbalance rotor 38 and the second imbalance rotor 44 at awhole number multiple vibration canceling rotation frequency 52 greaterthan the operational rotation frequency 26 while controlling therotational phase position of the first imbalance rotor eccentric massconcentration and the second imbalance rotor eccentric massconcentration inorder to produce a rotating net force vector 58 toinhibit the periodic vibration 24. Preferably the lubricant 48 is aliquid lubricant. Preferably the electronics control system 50 measuresthe periodic vibration 24 and controls the speed, the relative phase andthe absolute phase of the first coaxial brushless frameless AC ringmotor imbalance rotor 38 and the second coaxial brushless frameless ACring motor imbalance rotor 44. Preferably the provided housing 30includes a circumferential surface 74 that constrains the liquidlubricant 48, and the method includes rotating the rotary housing 30with the helicopter rotary wing hub at the operational rotationfrequency 26 with the liquid lubricant collecting at the circumferentialsurface 74. Preferably the method includes moving the liquid lubricant48 inward from the circumferential surface 74 towards the axis ofrotation 28. Preferably the first rotor 38 has a lubricated bearing 64for supporting the first rotor relative to the housing 30 and the secondrotor 44 has a lubricated bearing 66 for supporting the second rotorrelative to the housing 30, and the method includes moving the lubricantcollecting at the circumferential surface 74 through lubricatedbearings. Preferably the method includes sealing the liquid lubricant 48in the rotor cavities of housing 30. As shown in an embodiment in FIG.8, the first and second imbalance rotors 38 and 44 are coupled togetherwith a plurality of rotor detents 86, preferably detent magnets, suchthat the rotors can rotate together in the event of one of the motorsfailing. In an embodiment the method includes magnetically coupling thefirst rotor with the second rotor, preferably with magnetic detents 86such that the magnetically coupled rotors slip relative to each other ata prescribed torque. The method preferably includes that in the event ofa motor failure the other motor spins both rotors, with the relativeposition of the two rotor eccentric mass concentrations 40 and 46 variedby controlling acceleration impulses to the working motor to cause therotors to slip relative to each other. In preferred embodiments themethod includes isolating the first rotor 38 in a first rotor upperrotor cavity 60 from the second rotor 44 in a second rotor lower rotorcavity 62. Preferably the upper and lower outer cavities 60 and 62 areseparated so that particles, contaminates, and spall debris from onerotor does not contaminate the other, preferably with the upper andlower liquid lubricated outer cavities 60 and 62 liquidly isolated fromeach other. In an embodiment the housing rotor cavities aresubstantially completely filled with liquid lubricant 48. In anembodiment the housing rotor cavities are partially filled with liquidlubricant 48, preferably such that when housing 30 rotates at thehelicopter operational rotation frequency the lubricated bearings 64 and66 are lubricated by the liquid lubricant 48 but the rotor is notsubmerged in the liquid, preferably with the rotors rotating through anon-liquid gas. Preferably the method includes providing at least onehealth monitoring sensor 84 and monitoring a change in an operationalcharacteristic of the rotors and the vibration control system sensed bythe health monitoring sensors. Preferably the health monitoring sensor84 and its health monitoring system is incorporated into the electronicscontrol system 50. The health monitoring includes measuring operationalperformance characteristics of the vibration control system 20 withsensors 84, most preferably operational performance characteristics ofthe first and second rotors 38 and 44 and their rotation, andparticularly the performance of bearings 64 and 66. Preferably themethod includes monitoring the health of the rotor bearings 64 and 66with at least one sensor 84. In an embodiment the sensors 84 aretemperature sensors that monitor the temperature of the bearings for achange in bearing operation temperature that signals a bearing heat upand degradation in the operation of the bearing. Preferably the healthmonitoring system with sensors 84 includes at least two temperaturesensors, such as thermocouples, preferably with at least one adjacentthe bearing to monitor the bearing temperature. Preferably healthmonitoring the vibration control system includes utilizing a referencetemperature to determine when the bearing temperature is rising abovethe ambient temperature of the vibration control system 20. The healthmonitoring system sensors 84 monitor the bearing temperature differencesto determine if a bearing is heating up too much in its operation, andwhen the measured temperature difference exceeds a measured operationalperformance characteristic limitation, the vibration control system,preferably through the electronics system, provides for a correctionchange in the vibration control system, such as communicating andwarning the helicopter user and maintainers that bearing maintenanceand/or replacement should be performed so that the bearing operation iscorrected prior to failure of the bearing and its rotor. The healthmonitoring system sensors 84 preferably catches the operation problem atthe performance degradation stage, and provides a warning notificationto the helicopter operator or maintenance crew, to warn aboutreplacement prior to bearing operation failure. The health monitoringsystem is preferably linked with the helicopter avionics system, with awarning maintenance signal transmitted to the avionics system andoperator. In an embodiment the health monitoring method monitorsoperation trends and stores the sensor data, and prior to failure ofvibration control system operation identifies an approaching failure. Inan embodiment the provided health monitoring system sensors 84 areaccelerometers and the method monitors vibration signal levels at ballpass frequency bands to pickup on a deteriorating bearing race. Healthmonitoring system sensors 84 may be the accelerometers 72, or preferablyseparate accelerometer sensors 84 that monitor the ball pass frequencyfrom each time a ball rolls over a bearing race problem spot and makes avibration. Additionally in embodiments the health monitoring methodincludes sensing, monitoring, and warning about the vibration controlsystem operation including the currents, torques, and temperatures ofmotors 36 and 42. Preferably the health monitoring system sensors 84input data into a health monitoring system algorithm, with the algorithmoutputting a notification to affect a change/correction to the vibrationcontrol system 20 such as service or replacement. In an embodiment thehealth monitoring system algorithm outputs a log of collected sensordata that is downloaded and analyzed for performance and operationissues.

In an embodiment the invention includes a method of making a helicopterrotating hub mounted vibration control system 20 for a helicopter rotarywing hub 22 having a periodic vibration 24 while rotating at ahelicopter operational rotation frequency 26. The method includesproviding a rotary annular ring housing 30 having an electronics housingcavity subsystem 32 and a rotor housing cavity subsystem 34. Theprovided rotary annular ring housing 30 provides a structural means forrotating about the axis of rotation 28 at the helicopter operationalrotation frequency 26. The housing 30 is centered about the rotary winghub axis of rotation 28. The rotary housing contains a first coaxialbrushless frameless AC ring motor centered about and coaxially with therotary wing hub axis of rotation 28. The provided first coaxial ringmotor has a first rotor 38 with a first imbalance rotor eccentric massconcentration 40. The rotary housing contains a second coaxial brushlessframeless AC ring motor centered about and coaxial with the rotary winghub axis of rotation 28. The second ring motor 42 has a second rotor 44with a second imbalance rotor eccentric mass concentration 46.Preferably the rotary housing 30 has a circumferential surface 74.Preferably an electronics control system 50 is contained in the rotaryannular ring housing 30 with the electronics control system 50 rotatingwith the housing 30 about the axis of rotation 28 at the helicopteroperational rotation frequency 26. The electronics control system 50measures the periodic vibration and controls a speed, a relative phaseand an absolute phase of the first coaxial frameless ring motor and thesecond coaxial ring motor while rotating with the housing 30 about theaxis of rotation 28 at the helicopter operational rotation frequency 26.The method includes sealing a liquid lubricant 48 inside the housing 30,wherein the liquid lubricant 48 collects along the circumferentialsurface 74 when the housing rotates at the helicopter operationalrotation frequency. Preferably the electronics control system isdisposed in the housing so that the electronics control system 50rotates with the housing 30. Preferably providing the housing 30includes providing a housing 30 with a rotor housing cavity 34 comprisedof a first rotor upper cavity 60 and a second rotor lower cavity 62, andthe method includes isolating the first rotor 38 in the first rotorupper cavity 60 from the second rotor 44 in the second rotor lowercavity 62. Preferably the method includes providing a health monitoringsensor 84 for monitoring a change in an operational characteristic ofthe vibration control system and disposing the health monitoring sensor84 in the rotary housing. Preferably the health monitoring sensor 84 andits health monitoring system is incorporated into the electronicscontrol system 50. The health monitoring sensor 84 measures anoperational performance characteristic of the vibration control system20. Most preferably the sensors 84 are disposed proximate the rotors sothe operational performance characteristics of the first and secondrotors 38 and 44, and particularly the performance of bearings 64 and 66are monitored. Preferably the sensors 84 monitor the health of the rotorbearings 64 and 66. In an embodiment the sensors 84 are temperaturesensors, preferably thermocouples that monitor the temperature of thebearings for a change in bearing operation temperature that signals abearing heat up and degradation in the operation of the bearing.Preferably temperature sensors 84 are disposed adjacent the bearings 64and 66. Preferably the health monitoring sensors 84 are linked with theelectronics control system 50 and the helicopter avionics system suchthat when a measured characteristic exceeds a measured operationalperformance characteristic limitation, a warning is transmitted toprovide for a correction change in the vibration control system, such ascommunicating and warning the helicopter user and maintainers thatbearing maintenance and/or replacement should be performed so that thebearing operation is corrected prior to failure of the bearing and itsrotor. In an embodiment the provided health monitoring system sensors 84are accelerometers that monitor the ball pass frequency from each time aball rolls over a bearing race problem spot and makes a vibration.Additionally in embodiments the health monitoring sensors are sensorsfor monitoring and warning about the vibration control system operationincluding the currents, torques, and temperatures of motors 36 and 42.

In an embodiment the invention includes a vibration control helicopterrotating hub mounted vibration balancer 20, which rotates about a centeraxis of rotation 28 at an operational rotation frequency 26. Preferablythe vibration balancer is detachably attached to the helicopter rotorhub with the balancer rotating with the rotor shaft for controllingproblematic helicopter vibrations. As shown in FIG. 9, the vibrationbalancer 20 is comprised of a first stator 90 having a plurality ofelectromagnets 92 periodically spaced around the center axis of rotation28. The vibration balancer 20 is comprised of a first imbalance rotor 38having an eccentric mass concentration 40 and a plurality of permanentmagnets 94 periodically spaced around the center axis of rotation 28.The first imbalance rotor 38 is disposed around and adjacent to thefirst stator 90 with a bearing 64 providing for rotation of the rotorrelative to the housing 30. The vibration balancer 20 is comprised of asecond stator 96 having a plurality of electromagnets 98 periodicallyspaced around the center axis of rotation 28. The vibration balancer 20is comprised of a second imbalance rotor 44 having an eccentric massconcentration 46 and a plurality of permanent magnets 100 periodicallyspaced around the center axis of rotation 28. The second imbalance rotor44 is disposed around and adjacent to the second stator 96 with abearing 66 providing for rotation of the rotor relative to the housing30. The permanent magnets 94 are adjacent to and separated from theelectromagnets 92 with an air gap 102 wherein the first statorelectromagnets 92 directly drive the first imbalance rotor magnets 94and the first imbalance rotor eccentric mass concentration 40 around thecenter axis of rotation 28 at a vibration canceling rotation frequency52 greater than the operational rotation frequency 26. The permanentmagnets 100 are adjacent to and separated from the electromagnets 98with an air gap 102 wherein the second stator electromagnets 98 directlydrive the second imbalance rotor magnets 100 and the second imbalancerotor eccentric mass concentration 46 around the center axis of rotation28 at the vibration canceling rotation frequency 52. Preferably thefirst and second stators directly drive the first and second imbalancerotors at a vibration canceling rotation frequency 52 that is a wholenumber multiple of the operational rotation frequency, preferably withthe whole number multiple >1, more preferably with the whole numbermultiple >3 and most preferably with a whole number multiple N where Nequals the number of blades on the helicopter. The imbalance rotoreccentric mass concentrations are electromagnetically directly drivenwith controlled periodically modulated EM fields from the electromagnetswhich repel/attract the surrounding permanent magnets. The statorsdirectly drive the imbalance rotors with their eccentric massconcentrations, in that the rotors are gearlessly directly driven by theelectromagnetic fields generated by the electromagnets withoutmechanical gears coupling and transmitting the motion. Preferably thehousing 30 spins at the operational rotation frequency of 1 per rev andthe imbalance rotors are spinning at 4 per rev, which is 3 per revrelative to the housing 30 which is at 1 per rev. The directly drivenrotor 38 produces a first rotating force 54, and the second directlydriven rotor 44 produces a second rotating force 56, which combine toproduce a rotating net force vector 58 to balance out and cancel theperiodic rotating vibration force 24. The first imbalance rotor 38encompasses the first stator 90, and the second imbalance rotor 44encompasses the second stator 96, with the first imbalance rotor 44 andthe first stator 90 adjacent the second imbalance rotor 44 and thesecond stator 96 stacked and aligned coaxially. In an embodiment thefirst imbalance rotor eccentric mass concentration 40 is comprised of afirst imbalance mass arc and the second imbalance rotor eccentric massconcentration 46 is comprised of a second imbalance mass arc. Preferablythe imbalance mass arcs are made of a dense metal such as tungsten. Inan embodiment the imbalance mass arcs is incorporated into the structureof the rotor itself, such as with an arc section of the rotor formedfrom a dense metal structural material and the majority remainder of therotor formed from a relatively less dense metal structural material.Preferably the rotating vibration balancer includes a liquid lubricant48 contained by a rotary housing 30, preferably in a lubricated rotorhousing cavity subsystem 34. In a preferred embodiment the rotatingvibration hub balancer 20 includes an electronics housing cavitysubsystem 32 for containing a electronics control system 50, preferablywith the electronics housing cavity subsystem 32 unlubricated andfluidly sealed from the lubricated rotor housing cavity subsystem 34.Preferably the electronics control system 50 includes a plurality ofcontrol electronics and sensors for controlling the movement of theimbalance rotors 38 and 44. Preferably the stator electromagnet windingsare comprised of three phase motor windings. As shown in FIG. 9,preferably the first stator plurality of electromagnets 92 include afirst set of electromagnet windings 104 and a parallel adjacent secondset of electromagnet windings 106 and the second stator plurality ofelectromagnets 98 include a first set of electromagnet windings 104 anda parallel adjacent second set of electromagnet windings 106. Forexample, winding 104 and 106 are wound in a bifilar fashion. Preferablythe electronics control system 50 is comprised of a first stator firstamplifier 110 and a first stator second amplifier 112, with the firststator first amplifier 110 driving the first set of electromagnetwindings 104 and the first stator second amplifier 112 driving theadjacent second set of electromagnet windings 106. Preferably theelectronics control system 50 is comprised of a second stator firstamplifier 114 and a second stator second amplifier 116, with the secondstator first amplifier 114 driving the first set of electromagnetwindings 104 and the second stator second amplifier 116 driving theadjacent second set of electromagnet windings 106. Preferably the firstamplifiers and the second amplifiers are independently powerable andindependently controllable. Preferably each stator (90, 96) has two setsof electromagnetic windings (104 and 106), with each of the sets ofwinding having its own amplifier (110 and 112) (114 and 116). Preferablythe electronics control system includes four amplifiers, with thepreferred vibration control system operation utilizing two amplifiersdriving each imbalance rotor, with each amplifier and its set of statorelectromagnetic windings capable of driving the rotor by itselfindependent of the other amplifier and its windings. Preferably eachamplifier is comprised of a three-phase inverter. Preferably eachamplifier is comprised of three switching Amps, as shown in FIG. 9Dfirst stator first amplifier 110 is comprised of its first switching Amp120, second switching Amp 121, third switching Amp 122. As shown in FIG.9F first stator second amplifier 112 is comprised of its first switchingAmp 123, second switching Amp 124, and third switching Amp 125. As shownin FIG. 9D second stator first amplifier 114 is comprised of its firstswitching Amp 126, second switching Amp 127, and third switching Amp128. As shown in FIG. 9F second stator second amplifier 116 is comprisedof its first switching Amp 129, second switching Amp 130, and thirdswitching Amp 131. Preferably the rotary housing lubricated rotorhousing cavity subsystem 34 has an outer circumferential internal cavitysubsystem wall surface 74 with the first imbalance rotor 38 and thesecond imbalance rotor 44 rotating around the center axis of rotation 28at the vibration canceling rotation frequency 52 while the outercircumferential internal cavity subsystem wall surface 74 rotates aroundthe center axis of rotation 28 at the operational rotation frequency 26with centrifugal forces collecting the liquid lubricant 48 along thewall 74. Preferably the first imbalance rotor 38 includes a lubricantmover 76 for moving the lubricant 48, preferably a plurality ofprotrusions 76 that radially extend out into lubricant 48 held againsthousing cavity wall surface 74. Preferably the second imbalance rotor 44includes a lubricant mover 76 for moving the lubricant 48, preferably aplurality of protrusions 76 that radially extend out into lubricant 48held against housing cavity wall surface 74. Preferably the vibrationbalancer includes a plurality of lubricant movers 76 for moving thelubricant 48, preferably a plurality of radially extending protrusions76 that radially extend out into lubricant 48 held against housingcavity wall surface 74. The protrusions form a fluid disturbing wake inthe lubricant and cause it to splash into the bearings. In an embodimentthe lubricant movers 76 are anchored on the rotors. In an embodiment thelubricant movers 76 are anchored on the ball separators of the bearings64 and 66. Preferably a first imbalance rotor bearing assembly 64provides for the rotational movement of the first imbalance rotor 38relative to the housing 30, and a second imbalance rotor bearingassembly 66 provides for the rotational movement of the second imbalancerotor 44 relative to the housing 30. Preferably the first imbalancerotor bearing assembly 64 has an inner race 80 on the first imbalancerotor 38, an outer race 78 proximate the outer circumferential internalwall 74, and a plurality of rolling members 82 between the inner race 80and the outer race 78. Preferably the second imbalance rotor bearingassembly 66 has an inner race 80 on the second imbalance rotor 44, anouter race 78 proximate the outer circumferential internal wall 74, anda plurality of rolling members 82 between the inner race 80 and theouter race 78. Preferably the housing cavity, the volume of thelubricant, and the bearing assemblies are sized and oriented such thatat the operational rotation frequency 26 the lubricant collects againstthe wall with the lubricant at least contacting the inside diameter ofthe outer race. Preferably the operational rotation frequency 26 driveslubricant liquid 48 against the walls 74 and into contact with therolling members 82. In an embodiment the operational rotation frequency26 drives lubricant liquid 48 against the walls 74 with the rollingmembers 82 bathed and preferably partially submerged in the lubricantliquid 48. In an embodiment the housing cavity, the volume of thelubricant, and the bearing assemblies are sized and oriented such thatat the operational rotation frequency 26 the lubricant collects againstthe wall with the lubricant submerging the bearing outer race but notthe bearing inner race. In an embodiment the housing cavity, the volumeof the lubricant, and the bearing assemblies are sized and oriented suchthat at the operational rotation frequency 26 the lubricant collectsagainst the wall with the lubricant submerging the bearing outer racebut not the bearing ball separators. Preferably the vibration controlrotating hub 20 includes an annular ring rotary housing 30 centeredabout and encompassing the center axis of rotation 28, and morepreferably encompassing the rotor shaft 29 and rotating at theoperational rotation frequency. Preferably the annular ring rotaryhousing 30 contains the electronics control system 50, which rotateswith the housing around the center axis of rotation 28 with the rotorshaft 29 at the operational rotation frequency. Preferably the vibrationcontrol rotating hub 20 includes a health monitoring sensor 84 formonitoring a change in an operational characteristic of the vibrationcontrol rotating hub. Preferably the health monitoring sensors 84 andtheir health monitoring system are incorporated into the electronicscontrol system 50. The health monitoring system sensors 84 measureoperational performance characteristics of the vibration controlrotating hub system 20, most preferably the operational performancecharacteristics of the first and second rotors 38 and 44 and theirrotation. Preferably the sensors 84 monitor the health of the rotorbearings 64 and 66. In an embodiment the sensors 84 are temperaturesensors that monitor the temperature of the bearings for a change inbearing operation temperature that signals a bearing heat up anddegradation in the operation of the bearing. Preferably the healthmonitoring system with sensors 84 includes at least two temperaturesensors, such as thermocouples, preferably with at least one adjacentthe bearing to monitor the bearing temperature. Preferably the healthmonitoring system utilizes a reference temperature to determine when thebearing temperature is rising above the ambient temperature of thevibration control rotating hub system 20. The health monitoring systemsensors 84 monitor the bearing temperature differences to determine if abearing is heating up too much in its operation, and when the measuredtemperature difference exceeds a measured operational performancecharacteristic limitation, the vibration control system preferablythrough the electronics system provides for a correction change in thevibration control rotating hub, such as communicating and warning thehelicopter user and maintainers that bearing maintenance and/orreplacement should be performed so that the bearing operation iscorrected prior to failure of the bearing and rotation of the rotor. Thehealth monitoring system sensors 84 catches the operation problem at theperformance degradation stage, and provides a warning notification tothe helicopter operator or maintenance crew, to warn about replacementprior to bearing operation failure. The health monitoring system ispreferably linked with the helicopter avionics system, with a warningmaintenance signal transmitted to the avionics system and operator. Inan embodiment the health monitoring system sensors 84 monitors trends,with the system storing the sensor data and prior to failure ofvibration control rotating hub operation identify an approachingfailure. In an embodiment the health monitoring system sensors 84 areaccelerometers and monitor vibration signal levels at the ball passfrequency bands to pickup on a deteriorating bearing race. Healthmonitoring system sensors 84 may be the accelerometers 72, or preferablyseparate accelerometer sensors 84 that monitor the ball pass frequencyfrom each time a bearing ball rolls over a bearing race problem spot andmakes a vibration. Additionally in embodiments the health monitoringsystem senses, monitors, and warns about the vibration control rotatinghub operation including the currents, torques, and temperature of thestators and windings. Preferably the health monitoring system sensors 84inputs data into a health monitoring system algorithm, with thealgorithm outputting a notification to effect a change/correction to thevibration control rotating hub 20 such as service or replacement. In anembodiment the output of the health monitoring system algorithm is a logof collected sensor data that is downloaded and analyzed for performanceand operation issues.

Preferably the invention includes a method of controlling a periodicvibration of a helicopter with a helicopter rotary wing hub, whichrotates about a center axis of rotation at an operational rotationfrequency. The method includes providing a first stator 90 having aplurality of electromagnets 92 periodically spaced around the centeraxis of rotation 28. The method includes providing a first imbalancerotor 38 having an eccentric mass concentration 40 and including aplurality of permanent magnets 94 periodically spaced around the centeraxis of rotation 28. The method includes disposing and coupling thefirst imbalance rotor 38 around the first stator 90 such that the firststator electromagnets 92 gearlessly directly drive the first imbalancerotor magnets 94 and the first imbalance rotor eccentric massconcentration 40 around the center axis of rotation. The method includesproviding a second stator 96 having a plurality of electromagnets 98periodically spaced around the center axis of rotation 28. The methodincludes providing a second imbalance rotor 44 having an eccentric massconcentration 46, and a plurality of magnets 100 periodically spacedaround the center axis of rotation 28. The method includes disposing andcoupling the second imbalance rotor 44 around the second stator 96 suchthat the second stator electromagnets 98 directly drive the secondimbalance rotor magnets 100 and the second imbalance rotor eccentricmass concentration 46 around the center axis of rotation 28. The methodincludes directly driving the first rotor 38 and the second rotor 44 ata whole number multiple vibration canceling rotation frequency greaterthan the operational rotation frequency while controlling the rotationalposition of the first imbalance rotor eccentric mass concentration 40and the rotational position of the second imbalance rotor eccentric massconcentration 46 in order to produce a rotating net force vector 58 toinhibit the problematic periodic vibration. The first imbalance rotorencompasses the first stator, and the second imbalance rotor encompassesthe second stator, with the first imbalance rotor and the first statorstacked adjacent to the second imbalance rotor and the second stator andaligned coaxially. The rotors are preferably contained in an operationalrotation frequency rotary housing 30 spinning at the operationalrotation frequency 26, with the imbalance mass concentrationselectromagnetically driven at the vibration canceling rotationfrequency. The first imbalance rotor eccentric mass concentrationproduces a first rotating force, and the second imbalance rotoreccentric mass concentration produces a second rotating force, whichcombine to produce a rotating net force vector to cancel the periodicvibration force. Preferably providing the first stator 90 with aplurality of electromagnets 92 includes providing a first stator 90 witha first set of electromagnet windings 104 and an adjacent parallelsecond set of electromagnet windings 106. Preferably providing thesecond stator 96 having a plurality of electromagnets 98 includesproviding a second stator 96 with a first set of electromagnet windings104 and a second set of electromagnet windings 106. Preferably themethod includes providing an electronics control system 50, with theelectronics control system including a first stator first amplifier 110,a first stator second amplifier 112, a second stator first amplifier 114and a second stator second amplifier 116. Preferably the first statorfirst amplifier 110 drives the first stator first set of electromagnetwindings 104 and the first stator second amplifier 112 drives theadjacent second set of electromagnet windings 106. Preferably the secondstator first amplifier 114 drives the second stator first set ofelectromagnet windings 104 and the second stator second amplifier 116drives the adjacent second set of electromagnet windings 106. Preferablyin operation two amplifiers drive each imbalance rotor, most preferablywith each amplifier and its set of stator electromagnetic windingscapable of driving the rotor by itself independent of the otheramplifier and its windings. Preferably each amplifier is comprised ofthree switching Amps. Preferably the method includes driving animbalance rotor with just one set of windings and one amplifier,preferably when the other set of windings and/or amplifier fails orencounters problems. Preferably the method includes sealing the disposedand coupled first imbalance rotor and first stator and the disposed andcoupled second imbalance rotor and second stator in a housing 30 with aliquid lubricant 48. Preferably the housing 30 is comprised of a firstrotor upper cavity 60 and a second rotor lower cavity 62, and the methodincludes isolating the first rotor in the first rotor upper cavity fromthe second rotor in the second rotor lower cavity, preferably with theupper and lower liquid lubricated cavities liquidly isolated from eachother. Preferably the method includes providing a health monitoringsensor 84 and monitoring a change in an operational characteristic ofthe rotors sensed by the health monitoring sensor. Preferably the healthmonitoring sensor 84 and its health monitoring system is incorporatedinto the electronics control system 50. The health monitoring includesmeasuring operational performance characteristics of the vibrationcontrol system 20 with sensors 84, most preferably operationalperformance characteristics of the first and second rotors 38 and 44 andtheir rotation, and particularly the performance of bearings 64 and 66.Preferably the method includes monitoring the health of the rotorbearings 64 and 66 with at least one sensor 84. In an embodiment thesensors 84 are temperature sensors that monitor the temperature of thebearings for a change in bearing operation temperature that signals abearing heat up and degradation in the operation of the bearing.Preferably the health monitoring system with sensors 84 includes atleast two temperature sensors, such as thermocouples, preferably with atleast one adjacent the bearing to monitor the bearing temperature.Preferably health monitoring the vibration control system includesutilizing a reference temperature to determine when the bearingtemperature is rising above the ambient temperature of the vibrationcontrol system 20. The health monitoring system sensors 84 monitor thebearing temperature differences to determine if a bearing is heating uptoo much in its operation, and when the measured temperature differenceexceeds a measured operational performance characteristic limitation,the vibration control system preferably through the electronics systemprovides for a correction change in the vibration control system, suchas communicating and warning the user and maintainers that bearingmaintenance and/or replacement should be performed so that the bearingoperation is corrected prior to failure of the bearing and its rotor.The health monitoring system sensors 84 preferably catches the operationproblem at the performance degradation stage, and provides a warningnotification to the operator or maintenance crew, to warn aboutreplacement prior to bearing operation failure. The health monitoringsystem is preferably linked with a warning maintenance signaltransmitted to the operator. In an embodiment the health monitoringmethod monitors operation trends and stores the sensor data, and priorto failure of vibration control system operation identifies anapproaching failure. In an embodiment the provided health monitoringsystem sensors 84 are accelerometers and the method monitors vibrationsignal levels at ball pass frequency bands to pickup on a deterioratingbearing race. Health monitoring system sensors 84 may be theaccelerometers 72, or preferably separate accelerometer sensors 84 thatmonitor the ball pass frequency from each time a ball rolls over abearing race problem spot and makes a vibration. Additionally inembodiments the health monitoring method includes sensing, monitoring,and warning about the vibration control system operation including themotor's currents, torques, and temperatures. Preferably the healthmonitoring system sensors 84 input data into a health monitoring systemalgorithm, with the algorithm outputting a notification to affect achange/correction to the vibration control system 20 such as service orreplacement. In an embodiment the health monitoring system algorithmoutputs a log of collected sensor data that is downloaded and analyzedfor performance and operation issues.

In an embodiment the invention includes a rotating vibration balancercontrol system for a rotating machine having an operational rotationfrequency. The rotating vibration control system provides forcontrolling a rotating periodic disturbance vibration force of therotating machine. The rotating vibration balancer control system rotatesabout a center axis of rotation 28 at the operational rotation frequency26. The rotating vibration control system includes a first motor 36 withelectromagnets periodically spaced around the center axis of rotation28, preferably the first motor 36 is a brushless frameless AC ringmotor. The balancer includes a first imbalance rotor 38 with a massconcentration 40, with the first imbalance rotor including a pluralityof magnets periodically spaced around said center axis of rotation 28.Preferably the plurality of magnets include a plurality of rotor detentmagnets 86 periodically spaced along the circumference of the rotor. Thefirst imbalance rotor 38 and the first motor 36 are centered about saidaxis of rotation 28, with the first imbalance rotor driven by the firstmotor around the center axis of rotation at a vibration controllingrotation frequency 52 greater than said operational rotation frequency26. The rotating vibration control system includes a second imbalancerotor 44 having a mass concentration 46, with the second imbalance rotor44 centered about the axis of rotation 28 with the second imbalancerotor 44 proximate the first imbalance rotor 38 wherein the secondimbalance rotor mass concentration 46 is movable relative to the firstimbalance rotor inorder to produce a rotating balancing net force tominimize and cancel out the periodic vibration force. In an embodimentthe second imbalance rotor mass concentration 46 is movable relative tothe first imbalance rotor with a second motor 42 that moves the secondimbalance rotor 44. In an embodiment such as shown in FIG. 8E, the firstand second imbalance rotors 38 and 44 are coupled together with aplurality of rotor detent magnets 86, such that the rotors can rotatetogether in the event of one of the motors failing. The first rotor ismagnetically coupled to the second rotor with the magnetic detents 86such that the magnetically coupled rotors slip relative to each other ata prescribed torque. The relative position of the two rotor eccentricmass concentrations 40 and 46 can be varied by controlling accelerationimpulses to the motor to cause the rotors to slip relative to eachother. In an embodiment such as shown in FIG. 10, an electromagneticcoil 200 controllably generates a magnetic field that creates a magneticcircuit between the rotor detent magnets 86 along the circumference ofthe first and second imbalance rotors 38 and 44 that provides for therelative motion between the first and second rotors. As shown in FIG. 4,the first rotor produces a first rotating force 54 and the second rotorproduces a second rotating force 56 which combine to produce a rotatingnet force vector 58 rotating multiples faster than the operationalrotation frequency 26 to balance out the periodic vibration force 24.The invention includes a method of making a rotating vibration controldevice, which rotates about a center axis of rotation at an operationalrotation frequency. The rotating vibration control device for a rotatingmachine having a rotating periodic disturbance vibration when rotatingat the operational rotation frequency. The method includes providing anannular ring rotary housing 30. Preferably the housing 30 includes anelectronics housing cavity subsystem 32 and a rotor housing cavitysubsystem 34. Preferably the housing 30 is centered about the hub axisof rotation 28 with the electronics housing cavity subsystem 32 centeredabout the axis of rotation 28 and the rotor cavity subsystem 34preferably adjacent and coaxial with the electronics cavity 32.Preferably the method includes providing a first stator 90 having aplurality of electromagnets 92 periodically spaced around the centeraxis of rotation 28, and providing a first imbalance rotor 38 having aneccentric mass concentration 40 and including a plurality of permanentmagnets 94 periodically spaced around the center axis of rotation 28.Preferably the method includes coupling the first imbalance rotor withthe first stator such that the first stator electromagnets 92 directlydrive the first imbalance rotor magnets 94 and the first imbalance rotoreccentric mass concentration 40 around the center axis of rotation 28.Preferably the method includes providing a second stator 96 having aplurality of electromagnets 98 periodically spaced around the centeraxis of rotation 28. Preferably the method includes providing a secondimbalance rotor 44 having an eccentric mass concentration 46 andincluding a plurality of magnets 100 periodically spaced around thecenter axis of rotation 28. Preferably the method includes coupling thesecond imbalance rotor with the second stator such that the secondstator electromagnets 98 directly drive the second imbalance rotormagnets 100 and the second imbalance rotor eccentric mass concentration46 around the center axis of rotation 28. Preferably the method includessealing the coupled first imbalance rotor and the first stator and thecoupled second imbalance rotor and the second stator in the housing 30,most preferably with a liquid lubricant in the housing with the rotors,wherein the imbalance rotors are directly driven at a vibrationcanceling rotation frequency greater than the rotating machineoperational rotation frequency. Preferably the imbalance rotors aredirectly driven at a vibration canceling rotation frequency that is awhole number multiple of the rotating machine operational rotationfrequency. Preferably the housing 30 is comprised of a first rotor uppercavity 60 and a second rotor lower cavity 62, and the method includesisolating the first rotor 38 in the first rotor upper cavity 60 from thesecond rotor 44 in the second rotor lower cavity 62. Preferablyproviding the first stator having a plurality of electromagnets includesproviding a first stator 90 with a first set of electromagnet windings104 and an adjacent parallel second set of electromagnet windings 106and providing the second stator having a plurality of electromagnetsincludes providing a second stator 96 with a first set of electromagnetwindings 104 and a parallel second set of electromagnet windings 106.Preferably the method includes providing an electronics control system50, with the electronics control system including a first stator firstamplifier 110, a first stator second amplifier 112, a second statorfirst amplifier 114 and a second stator second amplifier 116, with thefirst stator first amplifier 110 driving the first stator first set ofelectromagnet windings 104, the first stator second amplifier 112driving the parallel first stator second set of electromagnet windings106, and with the second stator first amplifier 114 driving the secondstator first set of electromagnet windings 104 and the second statorsecond amplifier 116 driving the parallel second set of electromagnetwindings 106. Preferably the electronics control system 50 rotates aboutthe center axis of rotation 28 along with the housing 30 at theoperational rotation frequency 26. Preferably each stator has two setsof windings and connected amplifiers, with each set capable of drivingthe imbalance, with preferred operation having two amplifiers/two setsof windings driving each rotor, with a rotor driven with just one set ofwindings when an operation problem is encountered with the other set ofwindings and its amplifier. The method preferably includes providing ahealth monitoring sensor 84 for monitoring a change in an operationalcharacteristic of the rotating machine and disposing the healthmonitoring sensor in the rotary housing 30. The method preferablyincludes providing the health monitoring sensor 84 and preferablyincorporating the sensor 84 into the electronics control system 50 toprovide a health monitoring sensor system. The health monitoring sensor84 measures operational performance characteristics of the vibrationcontrol system 20. Most preferably the sensors 84 are disposed proximatethe rotors so the operational performance characteristics of the firstand second rotors 38 and 44, and particularly the performance ofbearings 64 and 66 are monitored. Preferably the sensors 84 monitor thehealth of the rotor bearings 64 and 66. In an embodiment the sensors 84are temperature sensors, preferably thermocouples that monitor thetemperature of the bearings for a change in bearing operationtemperature that signals a bearing heat up and degradation in theoperation of the bearing. Preferably temperature sensors 84 are disposedadjacent the bearings 64 and 66. Preferably the health monitoringsensors 84 are linked with the electronics control system 50 such thatwhen a measured characteristic exceeds a measured operationalperformance characteristic limitation, a warning is transmitted toprovide for a correction change in the vibration control system, such ascommunicating and warning the rotating machine user and maintainers thatbearing maintenance and/or replacement should be performed so that thebearing operation is corrected prior to failure of the bearing and itsrotor. In an embodiment the provided health monitoring system sensors 84are accelerometers that monitor the ball pass frequency from each time aball rolls over a bearing race problem spot and makes a vibration.Additionally in embodiments the health monitoring sensors are sensorsfor monitoring and warning about the vibration control system operationsuch as operational currents, torques, and temperatures.

In an embodiment the invention includes a method of making a helicopterrotating vibration balancer, which rotates about a center axis ofrotation at an operational rotation frequency. The method includesproviding an annular ring rotary housing 30. Preferably the housing 30includes an electronics housing cavity subsystem 32 and a rotor housingcavity subsystem 34. Preferably the housing 30 is centered about therotary wing hub axis of rotation 28 with the electronics housing cavitysubsystem 32 centered about axis of rotation 28 and the rotor cavitysubsystem 34 adjacent and coaxial with the electronics cavity 32.Preferably the method includes providing a first stator 90 having aplurality of electromagnets 92 periodically spaced around the centeraxis of rotation 28, and providing a first imbalance rotor 38 having aneccentric mass concentration 40 and including a plurality of permanentmagnets 94 periodically spaced around the center axis of rotation 28.Preferably the method includes coupling the first imbalance rotor aroundfirst stator such that the first stator electromagnets 92 directly drivethe first imbalance rotor magnets 94 and the first imbalance rotoreccentric mass concentration 40 around the center axis of rotation 28.Preferably the method includes providing a second stator 96 having aplurality of electromagnets 98 periodically spaced around the centeraxis of rotation 28. Preferably the method includes providing a secondimbalance rotor 44 having an eccentric mass concentration 46 andincluding a plurality of magnets 100 periodically spaced around thecenter axis of rotation 28. Preferably the method includes coupling thesecond imbalance rotor around the second stator such that the secondstator electromagnets 98 directly drive the second imbalance rotormagnets 100 and the second imbalance rotor eccentric mass concentration46 around the center axis of rotation 28. Preferably the method includessealing the coupled first imbalance rotor and the first stator and thecoupled second imbalance rotor and the second stator in the housing 30,most preferably with a liquid lubricant in the housing with the rotors.Preferably the housing 30 is comprised of a first rotor upper cavity 60and a second rotor lower cavity 62, and the method includes isolatingthe first rotor 38 in the first rotor upper cavity 60 from the secondrotor 44 in the second rotor lower cavity 62. Preferably providing thefirst stator having a plurality of electromagnets includes providing afirst stator 90 with a first set of electromagnet windings 104 and anadjacent parallel second set of electromagnet windings 106 and providingthe second stator having a plurality of electromagnets includesproviding a second stator 96 with a first set of electromagnet windings104 and a parallel second set of electromagnet windings 106. Preferablythe method includes providing an electronics control system 50, with theelectronics control system including a first stator first amplifier 110,a first stator second amplifier 112, a second stator first amplifier 114and a second stator second amplifier 116, with the first stator firstamplifier 110 driving the first stator first set of electromagnetwindings 104, the first stator second amplifier 112 driving the parallelfirst stator second set of electromagnet windings 106, and with thesecond stator first amplifier 114 driving the second stator first set ofelectromagnet windings 104 and the second stator second amplifier 116driving the parallel second set of electromagnet windings 106.Preferably the electronics control system 50 rotates about the centeraxis of rotation 28 along with the housing 30 at the operationalrotation frequency 26. Preferably each stator has two sets of windingsand connected amplifiers, with each set capable of driving theimbalance, with preferred operation of the helicopter rotating hub 20having two amplifiers/two sets of windings driving each rotor, with arotor driven with just one set of windings when a operation problem isencountered with the other set of windings and its amplifier. The methodpreferably includes providing a health monitoring sensor 84 formonitoring a change in an operational characteristic of the helicopterrotating hub and disposing the health monitoring sensor in the rotaryhousing 30. The method preferably includes providing the healthmonitoring sensor 84 and preferably incorporating the sensor 84 into theelectronics control system 50 to provide a health monitoring sensorsystem. The health monitoring sensor 84 measures an operationalperformance characteristic of the vibration control system 20. Mostpreferably the sensors 84 are disposed proximate the rotors so theoperational performance characteristics of the first and second rotors38 and 44, and particularly the performance of bearings 64 and 66 aremonitored. Preferably the sensors 84 monitor the health of the rotorbearings 64 and 66. In an embodiment the sensors 84 are temperaturesensors, preferably thermocouples that monitor the temperature of thebearings for a change in bearing operation temperature that signals abearing heat up and degradation in the operation of the bearing.Preferably temperature sensors 84 are disposed adjacent the bearings 64and 66. Preferably the health monitoring sensors 84 are linked with theelectronics control system 50 and the helicopter avionics system suchthat when a measured characteristic exceeds a measured operationalperformance characteristic limitation, a warning is transmitted toprovide for a correction change in the vibration control system, such ascommunicating and warning the helicopter user and maintainers thatbearing maintenance and/or replacement should be performed so that thebearing operation is corrected prior to failure of the bearing and itsrotor. In an embodiment the provided health monitoring system sensors 84accelerometers that monitor the ball pass frequency from each time aball rolls over a bearing race problem spot and makes a vibration.Additionally in embodiments the health monitoring sensors are sensorsfor monitoring and warning about the vibration control system operationsuch as operational currents, torques, and temperatures.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the invention withoutdeparting from the spirit and scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents. It is intended that the scope ofdiffering terms or phrases in the claims may be fulfilled by the same ordifferent structure(s) or step(s).

1. A rotary wing aircraft rotating vibration control system for anaircraft rotary wing hub having a periodic vibration while rotating at arotary wing aircraft operational rotation frequency about a rotary wingaxis of rotation, said rotary wing aircraft rotating vibration controlsystem comprised of: a rotary housing, said housing centered about andencompassing said rotary wing axis of rotation and rotating with saidrotary wing hub at said operational rotation frequency, said housingcontaining a first coaxial ring motor coaxially centered about saidrotary wing axis of rotation, said first coaxial ring motor having afirst rotor with a first imbalance mass concentration, said housingcontaining a second coaxial ring motor coaxially centered about saidrotary wing axis of rotation, said second coaxial ring motor having asecond rotor with a second imbalance mass concentration; and anelectronics control system which controls a speed and a phase of saidfirst coaxial ring motor and a speed and a phase of said second coaxialring motor to drive said first imbalance mass concentration and saidsecond imbalance mass concentration wherein said rotary wing hubperiodic vibration is reduced.
 2. A rotating vibration control system asclaimed in claim 1 wherein said rotary housing confines a lubricant. 3.A rotating vibration control system as claimed in claim 1 wherein saidhousing is comprised of a first upper cavity and a second lower cavity.4. A rotating vibration control system as claimed in claim 1 whereinsaid first coaxial ring motor first rotor has a lubricated bearing forsupporting said first rotor relative to said housing, said first rotorbearing lubricated by a lubricant, and said second coaxial ring motorsecond rotor has a lubricated bearing for supporting said second rotorrelative to said housing, said second rotor bearing lubricated by alubricant.
 5. A rotating vibration control system as claimed in claim 4,wherein said housing includes a circumferential surface that constrainssaid lubricant.
 6. A rotating vibration control system as claimed inclaim 5, said first rotor lubricated bearing including an outer racesecured to said housing proximate said housing circumferential surfaceand an inner race secured to said first rotor, said second rotorlubricated bearing including an outer race secured to said housingproximate said housing circumferential surface and an inner race securedto said second rotor.
 7. A rotating vibration control system as claimedin claim 1 including a health monitoring sensor for monitoring a changein an operational characteristic of said vibration control system.
 8. Arotating vibration control system as claimed in claim 1 wherein saidelectronics control system includes an electromagnetic braking circuitfor electromagnetically braking a rotation of said rotors.
 9. A rotatingvibration control system as claimed in claim 1 wherein said electronicscontrol system opposingly orients said first imbalance massconcentration and said second imbalance mass concentration at atransitioning rotation speed.
 10. A method of controlling a periodicvibration of an aircraft with a rotary hub which rotates at anoperational rotation frequency, said method including providing anannular ring housing having a coaxial rotor housing cavity subsystem,said rotor housing cavity subsystem containing a first coaxial ringmotor having a first rotor with a first imbalance mass concentration, asecond coaxial ring motor having a second rotor with a second imbalancemass concentration, and a lubricant, securing said annular ring housingto said rotary hub with said annular ring housing rotating at saidoperational rotation frequency with said rotary hub, directly drivingthe rotation of said first rotor and said second rotor by controllingsaid first coaxial ring motor and said second coaxial ring motor tocontrol the rotational position of said first imbalance massconcentration and said second imbalance mass concentration inorder toinhibit said periodic vibration.
 11. A method as claimed in claim 10wherein said rotor housing cavity subsystem includes a circumferentialsurface that constrains said lubricant, and said method includesrotating said annular ring housing with said rotary hub at saidoperational rotation frequency with said lubricant collecting at saidcircumferential surface.
 12. A method as claimed in claim 11 includingmoving said lubricant inward from said circumferential surface.
 13. Amethod as claimed in claim 11 wherein said first rotor has a lubricatedbearing for supporting said first rotor relative to said housing andsaid second rotor has a lubricated bearing for supporting said secondrotor relative to said housing, and said method include moving saidlubricated bearings through said lubricant collecting at saidcircumferential surface.
 14. A method as claimed in claim 10 includingsealing said lubricant in said rotor cavity subsystem.
 15. A method asclaimed in claim 10, said method including isolating said first rotor ina first rotor upper rotor cavity from said second rotor in a secondrotor lower rotor cavity.
 16. A method as claimed in claim 10, saidmethod including providing a health monitoring sensor and monitoring achange in an operational characteristic sensed by said health monitoringsensor.
 17. A method as claimed in claim 10 wherein said method includeselectromagnetically braking a rotation of said rotors.
 18. A method asclaimed in claim 10 wherein said method includes opposingly orientingsaid first imbalance mass concentration and said second imbalance massconcentration at a transitioning rotation speed less.
 19. A method ofmaking a rotating hub mounted vibration control system for a rotary winghub having a periodic vibration while rotating at an operationalrotation frequency, said method including: providing a rotary housinghaving a rotor housing cavity, said rotor housing cavity containing afirst coaxial ring motor having a first rotor with a first imbalancemass concentration, a second coaxial ring motor having a second rotorwith a second imbalance mass concentration, said rotor housing cavityincluding a circumferential surface, providing an electronics controlsystem which controls a speed and a phase of said first coaxial ringmotor and a speed and a phase of said second coaxial ring motor,connecting said electronics control system with said first coaxial ringmotor and said second coaxial ring motor, and sealing a lubricant insidesaid rotor housing cavity, wherein said lubricant collects along saidcircumferential surface when said rotary housing rotates at saidoperational rotation frequency.
 20. A method as claimed in claim 19,wherein said rotor housing cavity is comprised of a first rotor uppercavity and a second rotor lower cavity, and said method includesisolating said first rotor in said first rotor upper cavity from saidsecond rotor in said second rotor lower cavity.
 21. A method as claimedin claim 19, said method including providing a health monitoring sensorfor monitoring a change in an operational characteristic and disposingsaid health monitoring sensor in said rotary housing.
 22. A rotatingvibration control system for a rotating machine having an operationalrotation frequency which rotates about a center axis of rotation at saidoperational rotation frequency, said rotating vibration control systemcomprised of a rotating vibration control system rotary housing, saidrotary housing centered about and encompassing said center axis ofrotation, said rotary housing rotating about said center axis at saidoperational rotation frequency, said rotary housing including a firststator having a plurality of electromagnets, said electromagnetsperiodically spaced around said center axis of rotation, a firstimbalance rotor having a mass concentration, said first imbalance rotorincluding a plurality of magnets periodically spaced around said centeraxis of rotation, said first imbalance rotor adjacent said first stator,a second stator having a plurality of electromagnets, saidelectromagnets periodically spaced around said center axis of rotation,a second imbalance rotor having a mass concentration, said secondimbalance rotor including a plurality of magnets periodically spacedaround said center axis of rotation, said second imbalance rotoradjacent said second stator, wherein said first stator electromagnetsdirectly drive said first imbalance rotor magnets and said firstimbalance rotor mass concentration around said center axis of rotationat a first imbalance rotor vibration controlling rotation frequencygreater than said operational rotation frequency, and said second statorelectromagnets directly drive said second imbalance rotor magnets andsaid second imbalance rotor mass concentration around said center axisof rotation at a second imbalance rotor vibration controlling rotationfrequency; and a electronics control system which controls a speed and aphase of said first rotor and said second rotor.
 23. A rotatingvibration control system as claimed in claim 22 including a healthmonitoring sensor for monitoring a change in an operationalcharacteristic of said rotating vibration control system.
 24. A methodof controlling a periodic vibration of an aircraft with a rotary winghub which rotates about a rotary wing hub center axis of rotation at anoperational rotation frequency, said method including: providing a firststator having a plurality of electromagnets, said electromagnetsperiodically spaced around said rotary wing hub center axis of rotation,providing a first imbalance rotor, said first imbalance rotor having aneccentric mass concentration, said first imbalance rotor including aplurality of magnets periodically spaced around said rotary wing hubcenter axis of rotation, disposing and coupling said first imbalancerotor around said first stator such that said first statorelectromagnets directly drive said first imbalance rotor magnets andsaid first imbalance rotor eccentric mass concentration around saidrotary wing hub center axis of rotation, providing a second statorhaving a plurality of electromagnets, said electromagnets periodicallyspaced around said rotary wing hub center axis of rotation, providing asecond imbalance rotor, said second imbalance rotor having an eccentricmass concentration, said second imbalance rotor including a plurality ofmagnets periodically spaced around said rotary wing hub center axis ofrotation, disposing and coupling said second imbalance rotor around saidsecond stator such that said second stator electromagnets directly drivesaid second imbalance rotor magnets and said second imbalance rotoreccentric mass concentration around said rotary wing hub center axis ofrotation, directly driving said first rotor at a first rotor controllingrotation frequency greater than said operational rotation frequencyaround said rotary wing hub center axis of rotation and directly drivingsaid second rotor at a second rotor controlling rotation frequencygreater than said operational rotation frequency around said rotary winghub center axis of rotation while controlling a rotational position ofsaid first imbalance rotor eccentric mass concentration around saidrotary wing hub center axis of rotation and a rotational position ofsaid second imbalance rotor eccentric mass concentration around saidrotary wing hub center axis of rotation inorder to inhibit said periodicvibration.
 25. A method as claimed in claim 24 wherein providing saidfirst stator having a plurality of electromagnets includes providing afirst stator with a first set of electromagnet windings and a second setof electromagnet windings and providing said second stator having aplurality of electromagnets includes providing a second stator with afirst set of electromagnet windings and a second set of electromagnetwindings.
 26. A method as claimed in claim 24 including providing anelectronics control system, with said electronics control systemincluding a first stator first amplifier, a first stator secondamplifier, a second stator first amplifier and a second stator secondamplifier, and providing said first stator having a plurality ofelectromagnets includes providing a first stator with a first set ofelectromagnet windings and a second set of electromagnet windings, withsaid first stator first amplifier driving said first set ofelectromagnet windings and said first stator second amplifier drivingsaid second set of electromagnet windings, and providing said secondstator having a plurality of electromagnets includes providing a secondstator with a first set of electromagnet windings and a second set ofelectromagnet windings, with said second stator first amplifier drivingsaid first set of electromagnet windings and said second stator secondamplifier driving said second set of electromagnet windings.
 27. Amethod as claimed in claim 24, said method including sealing saiddisposed and coupled first imbalance rotor and first stator and saiddisposed and coupled second imbalance rotor and second stator in ahousing with a liquid lubricant.
 28. A method as claimed in claim 27,wherein said housing is comprised of a first rotor upper cavity and asecond rotor lower cavity, and said method includes isolating said firstrotor in said first rotor upper cavity from said second rotor in saidsecond rotor lower cavity.
 29. A method as claimed in claim 24, saidmethod including providing a health monitoring sensor and monitoring achange in an operational characteristic sensed by said health monitoringsensor.
 30. A rotating vibration control system which rotates about acenter axis of rotation at an operational rotation frequency, saidrotating vibration control system for balancing out a periodic vibrationforce, said rotating vibration control system comprised of a first motorhaving a plurality of electromagnets, said electromagnets periodicallyspaced around said center axis of rotation, a first imbalance rotorhaving a mass concentration, said first imbalance rotor including aplurality of magnets periodically spaced around said center axis ofrotation, said first imbalance rotor and said first motor centered aboutsaid axis of rotation, said first imbalance rotor driven by said firstmotor around said center axis of rotation at a vibration controllingrotation frequency greater than said operational rotation frequency, anda second imbalance rotor, said second imbalance rotor having a massconcentration, said second imbalance rotor centered about said axis ofrotation wherein said second imbalance rotor mass concentration ismovable relative to said first imbalance rotor mass concentrationinorder to produce a rotating balancing net force to cancel out saidperiodic vibration force.
 31. A method of making a rotating vibrationcontrol device which rotates about a center axis of rotation at anoperational rotation frequency, said method comprised of: providing arotary housing, providing a first stator having a plurality ofelectromagnets, said electromagnets periodically spaced around saidcenter axis of rotation, providing a first imbalance rotor, said firstimbalance rotor having an eccentric mass concentration, said firstimbalance rotor including a plurality of magnets periodically spacedaround said center axis of rotation, coupling said first imbalance rotoraround first stator such that said first stator electromagnets directlydrive said first imbalance rotor magnets and said first imbalance rotoreccentric mass concentration around said center axis of rotation,providing a second stator having a plurality of electromagnets, saidelectromagnets periodically spaced around said center axis of rotation,providing a second imbalance rotor, said second imbalance rotor havingan eccentric mass concentration, said second imbalance rotor including aplurality of magnets periodically spaced around said center axis ofrotation, coupling said second imbalance rotor around said second statorsuch that said second stator electromagnets directly drive said secondimbalance rotor magnets and said second imbalance rotor eccentric massconcentration around said center axis of rotation, sealing said coupledfirst imbalance rotor and said first stator and said coupled secondimbalance rotor and said second stator in said housing.
 32. A method asclaimed in claim 31, wherein said housing is comprised of a first rotorupper cavity and a second rotor lower cavity, and said method includesisolating said first rotor in said first rotor upper cavity from saidsecond rotor in said second rotor lower cavity.
 33. A method as claimedin claim 31 wherein providing said first stator having a plurality ofelectromagnets includes providing a first stator with a first set ofelectromagnet windings and a second set of electromagnet windings andproviding said second stator having a plurality of electromagnetsincludes providing a second stator with a first set of electromagnetwindings and a second set of electromagnet windings.
 34. A method asclaimed in claim 31 including providing an electronics control system,with said electronics control system including a first stator firstamplifier, a first stator second amplifier, a second stator firstamplifier and a second stator second amplifier, and providing said firststator having a plurality of electromagnets includes providing a firststator with a first set of electromagnet windings and a second set ofelectromagnet windings, with said first stator first amplifier drivingsaid first set of electromagnet windings and said first stator secondamplifier driving said second set of electromagnet windings, andproviding said second stator having a plurality of electromagnetsincludes providing a second stator with a first set of electromagnetwindings and a second set of electromagnet windings, with said secondstator first amplifier driving said first set of electromagnet windingsand said second stator second amplifier driving said second set ofelectromagnet windings.
 35. A method as claimed in claim 31, said methodincluding providing a health monitoring sensor for monitoring a changein an operational characteristic and disposing said health monitoringsensor in said rotary housing.